When electroplating a substrate it is common to attach the substrate to a rack to facilitate movement of the substrate. For a rigid substrate, the substrate is typically attached by clamping one edge of the substrate to one side of the rack. In such an instance, the rigidity of the substrate is sufficient to maintain the body of the substrate in position even though only one edge is fastened to the rack.
A common clamp used for rigid substrates is the screw-down type in which a threaded shaft acts in the manner of a set screw and is turned so that it contacts the substrate and presses the substrate against a portion of the clamp to hold it in place. Such a clamp is generally used to form an electrical connection between a conductive/seed layer on the substrate and a power source such that the seed layer acts as an electrode during electroplating.
Methods and devices for rigid substrates are generally unsuitable for use with flexible substrates. One difficulty encountered in applying rigid substrate methods to flexible substrates is that the method of clamping a rigid substrate to a substrate rack tends to damage the substrate. Another difficulty is that the current levels used for a rigid substrates tend to burn off the conductive/seed layers of a flexible substrate. Thus, there is a continuing need for new methods and devices for use in electroplating flexible substrates.